Low pressure tire indicator



April 14, 1959 E. F. coRDELL Low PRESSURE TIRE INDICATOR 2 Sheets-Sheet 1 Filed Sept. 8, 1955 E. E CORDELL INVENTOR FIG. l

ATTORNEY April 14, 1959 E. F. coRDr-:LL

LOW PRESSURE TIRE INDICATOR 2 Sheets-Sheet 2 Filed Sept. 8, 1955 FIG. 4

INVENTOR.

ATTORNEY `2,832,363 Low PRESSURE Tuin lNnlcAroR y E. F. coraeu, Lubbeek, rex.

' Appuctin september `s, 195s, serial No. 533,118 zfclaims. `v(cl. `zoof61.z6)

' vThe present invention relates to the trucking industry, and more particularly to a pneumatic tire pressure indicating switch.l j

,In the trucking o r transporting industry where large and heavy loads are'carried, it is desirable for the driver to receive `a warning that one or more of the tires is losing or has lost: its pressure. Most large transport trucks use dual wheels and tires in order to comply with the various States highway regulations and to properly support the load. One of the tires of the dual wheels may lose its pressure, thus placing an undue load on the United ,States PattOice remaining tire" and, yin many instances, ruining one or both tires before the ydriver is aware of the iat tire.

The lprior art reveals pressure indicating switches which lfeaturepressurized fluid reservoirs or diaphragms actuatedby the tire pressure. The primary objection to these devices lies in the necessity of maintaining the uid reservoirs leak proof and in replacing the diaphragms when the same become ruptured.

The primary object of the present invention is to pro vide a low pressure indicating switch for each individual tire.v

An additional object is to provide a low pressure indicating switch which illuminates a signal lamp visible to the driver when the pressure in any one of the tires is relieved.

A further object of this invention is to provide a signaling means to warn the driver of a vehicle that the pressure is low in a tire, thus possibly preventing an accident.

A still further object of this invention is to provide a low pressure indicating switch which is comparatively easily installed on a vehicle tire rim and thereafter remains in position and needs no further servicing or care.

An additional object is to provide a device of this class which is reliable and positive in its operation.

Another object is to provide a device of this class which has its actuating spring mounted external of the movable cylinder rather than internally thereof.

The present invention accomplishes these and other objects by providing a cylindrical plug-like body having a shank -end adapted to be threadedly engaged through a tire mounting rim on a vehicle. The body is centrally bored with enlarged annular recesses at each end of the bore. A spring actuated plunger or rod is slidably mounted in the bore of the body and has an annular ange or circular head on its inner end contacting the tire tube. A disk is threadedly connected to the outer end of the rod within the body. An electrical insulated screw projects laterally through the wall of the body from the enlarged recess of its outer end. Electrical wiring connects the screw to an electrically insulated ring carried by the wheel. A carbon brush carried by the vehicle in contact with the insulated ring is connected to a lamp by electrical wiring. 'Ihe disk is spaced from the screw head by pressure within the tube and the rod is actuated by the spring to contact the disk with the screw head 2,882,363 YPatented Apr". 14, 1959- Z and complete the electrical circuit and light the lamp when the pressure is relieved.

Other objects will be apparent from the following description when taken in conjunction with the accompanying two sheets of drawings, wherein:

. Figure 1- is a vertical cross sectional view, partly in elevation, of a vehicle dual wheel illustrating the installation of the invention thereon, the tires being shown by dotted lines;

Figure 2 is a vertical cross sectional view of the instant invention installed onv aitire rim with. a fragment of the tire and tube being shown in dotted lines;

Figure 3 is a fragmentary perspective view of the elec' trical conductor brush of the invention in contact with the conductor ring as shown in dotted lines; and,

Figure 4 is a schematic view of the electrical connections of the invention.

Like characters of reference designate like parts in those figures of. the drawings in which they occur.

In the drawings: v

The reference numerals 10 and 12 indicate, as a whole, a pair of wheels mounted in a conventional manner on a vehicle hub 14 carried by an axle 16. The hub 14 carries a brake drum 18. A brake disk 20 rigidly carried by the axle closes the brake drum in a conventional manner. Each wheel carries a tire rim 22, a tire 24, and a tube 26. The above description isA conventional with vehi. cles, particularly trucks, and forms no partof the instant invention other than to show a workable combination of vehicle parts for the installation of the device.

Referring now more particularly to Fig. 2, the reference numeral 30 indicates, as a whole, the switch of the present invention which is cylindrical in general configuration. The switch-v 30 includes a body 32 having an outer end 34 and an externally threaded shank end 36 of reduced size which is engaged within a threaded perf foration placed at a selected point in the flat portion of the tire rim 22. The body 32 and shank 36 are axially through bored, as at 38. The bore is concentrically enlarged from the shank end 36 to provide a first recess or spring receiving socket 40. The shank end of the bore is further concentrically enlarged to provide a second annular recess 42 of a selected depth. The bore at the outer end 34 of the body is enlarged to provide an annular recess 44 of a selected depth. The body 32 is further provided with a lateral perforation 46 through its wall in communication with the inner end of the recess 44, for the purposes more fully explained hereinbelow.

A plunger or rod 48 is slidably disposed within the bore 38 and has an integral annular tlange or circular head 50 which is slidably received by the recess 42 of the shank end. A disk 52 is axially threaded on the end of the rod opposite the ange 50 and is slidably received within the recess 44. Longitudinally the rod 48 is slightly less than the combined length of the body 32 and its shank 36 and is such that with the annular ange 50 seated on the inward end surface of the recess 42, the disk is disposed substantially adjacent the end 34 of the body. A helical expansion spring 54 is placed within the socket 40 around the rod 48 with one end of the spring seated against the annular shoulder formed by the inner end of the socket and its opposite end seated against the flange 50.

A screw 56 having a semispherical head is placed within the lateral bore 46 with the head projecting into the recess 44 and the other end of the screw extending beyond the wall of the body 32. The screw is electrically insulated from contact with the body 32 by washers 58 and a sleeve 60. A cap 62 seals the outer end 34 of the body and is held in place by an annular groove 63 in the surface of the body.

.. substantially transversely fiat surfaced electrical cnoni l drum 18 of the vehicle androtates therewith (Fig. 1),

Electric wiring ,68 connects the screw 56,V` v`itl1` the ,conductor ring 64. A carbon \brus1170'is rigidly carried by a' pairgf` non-conductive arms 72 pivotlly .Connected to a bracket 74 which is rigidly `carried by the brake shield ,20. The brush 70 is heldin sliding contact with the surface of the revolvingconductor ring titl.l by a, spring 76in a cor,iventional.,manner, Electric wiring 78 connects vthe brush `7.0 with the vehicle electrical system 'through a lamp 80.

Operation' with the'device'- installe; as'dis'eie'se ie'in'abnv'e, the

pressure withinth Vt1'1b`e`2'6 forces the' same against the annular Hnge' vso wliien fields the' disk 52 in' spacedina- :innl with the nene nffiie sgravi' s6. when the pressure is; relievedA within the eine 26 the' tieiici spring 54 nannies the' rod 48 to` move' the disk 52l into" contact *v ith: the screw head, as shown by dotted linesi'ny Fi'g' 2, which com# pletes' a'n electric circuit from the positive terminal of the battery through' the lamp 80, the Wiring" 78'; brush' 70, conductor ring 6 4, wiring 68, w disk 52,'r and which is grounded' by the b dy 32 and the yehi'ci'e f rni'e indicated by the line 82' (Fig, 4)', backh fo the battery in iunniin'at'e the signal lampi` 80', Obviously the helical spring 5 4 may be made with various" desired tensions' to actuate the rod 48' at' predetermined pressires.' Obviously the' inventionis susceptible to' some change' or alteration' without defeating its: pacticabilit'y, and` I therefore do net wish to Be cnnin'ed' t' the" preferred einfbodinient she'vtnjV in the drawings" and described herein', further than' I am limited by the scope of the appended clair's.`

regimi i i, 1'. A inw pressure inuieting `s'iififh fora pneumatic tire'and tube mounted onthe rim' f avehicle vwheel including/ a substantially cylindrical' body having an axial bore and :in axial" screw-'threaded' shank at its inner end for engagement with a complementary opening in the rim. from the exterior of the rim, the bore being enlarged at its ends to provide concentric recesses and form an annular shoulder therebetween, a rod complementary to and slidable in said bore, an enlarged head on one end of the rod and complementary to and reciprocable within the recess at the shank end of the body for engagement with the tube ,through'rthe opening of the rim, a helical lspringf,c triiirieglo 1rsaid rodnbetween; the head and the shoulder f said bore and in its shank end recess for urging Sladbeaitintg engagement `with the tube, an electrical mcontact disk on the oppositejend of said rod and ednipinieiifary to anti reipi'ca'bie iii the recess at the outer end Ti sa it i body/ ,'msaidbgdywhaving a lateral opening communicating with said outer recess adjacent said shoulder, an electrical contact element extending through the opening for engagement by the disk when the, for@ f.fh9 Spring. Qyetgnaeshapressure in, .the tube-' fd II'l 'HS iilh'e O'Plig. insulating fheclnt'at element frx said body; the length of said bore and itsf recesses being greater lthan the combined length of said 'dthwd and d isl(` whereby said disk is held out of en g'ge'r'nnt with sid' contact elenient yby thenibe pressure,- 2. lw pressure indicatingswtch as s et` forth in' l 1 wh ,n the har Si Xfi1siil wfh the bdy, and a cap Afritti ciially engaged on theouter end of sid body for lclosing the outer end of the outer recess:

limfeie-iics Cited*v lie of this patent NIT STATES PATENTS 

